The invention is in the field of wheelchair lifts for vehicles and is one of a series of lifts and closely related mechanisms patented or pending which have been applied for by the instant inventor, alone or with co-inventors working for the corporation to which this invention is assigned. These patents and applications include U.S. Pat. Nos. 4,081,091 issued Mar. 28, 1978; 4,027,807 issued June 7, 1977; 4,176,999 issued Dec. 4, 1979; 4,251,179 issued Feb. 17, 1981; pending application Ser. No. 06/268,466, which is a continuation-in-part of a patent cooperation treaty application which was in turn a continuation-in-part of U.S. Pat. No. 4,251,179. In addition, an application has just been filed on an auxiliary step for the two-step steplift of the type described in the above-referenced patents and patent applications.
The above-referenced applications and patents generally pertained to stair structure which could be extended into a horizontal platform which moved vertically between curb level and the floor level of a passenger bus to lift and lower wheelchairs. These units are mounted in either large or small commercial buses. The last mentioned patent application for an auxiliary step adapted the basic commercial bus steplift for use in applications such as on railroad and trolley cars wherein two steps were not enough to reach from the vehicle floor to the surrounding platform area when the unit was deployed as a stair.
The thrust of the instant invention is somewhat different than those mentioned above. Rather than representing a lift characterized by its ability to easily and simply define a stairway when not used as a lift, the instant lift does not define a stairway, but instead is adapted for use in a common van rather than a commercial bus.
The design criteria for a van-mounted unit are, that the unit be as compact as possible when not deployed, that it be very easily deployed, and that it be inexpensively and easily mounted on an existing van without requiring involved structural changes to the van. There are lifts for vans available, but typically they are characterized either by occupying a large space within the van even when not in use, or requiring considerable cutting and reshaping of the van, or both of these inconveniences may occur in the same unit.
The objects of this invention are precisely those stated as the design criteria for a good van-mounted lift. That is, that it be easily and economically mounted as a retrofit item on an existing van, that it be very compact when not in use, that it be easily deployed for use, and of course, that it be rugged and safe in operation.
Although the central thrust of the invention is for implementation in vans, the lift is by no means limited to vans. It would be equally useful in a motor home, or in a trailer; even if the trailer were parked and used as a home in a trailer park. In this last mentioned implementation, the lift would not only be useful for lifting wheelchair victims between ground level and trailer level, but could also be used to lift food and supplies to the level of the trailer floor.